Abstract
Symbioses have shaped our modern world, providing for the air we breathe; for
the plant and animal diversity we celebrate; and for the functioning of ecosystems from
the tops of mountains to the ocean floor. Here I study symbiosis using fungal bacterial
interactions as a model for understanding symbiotic dynamics. In this dissertation I
present interpretations of experimental data about fungal bacterial interactions that lend
insight into dynamics of symbiotic establishment and consequences of long-term
endosymbiosis. More specifically, I examine the interactions of a plant-associated
zygomycete, Mortierella elongata, and its interactions with several Betaproteobacteria in
the Burkholderiales. I used genome sequencing, comparative genomics, physiological
assays, and time-lapse microfluidic videography to ask the following questions; How
are bacterial fungal symbioses initiated? How do bacteria and fungi communicate? What
resources do these microbes share? Are long-term symbioses essential for one or both
partners? What are the impacts of removing long-term endosymbionts for fungal host
physiology? What are the effects long-term fungal endosymbiosis on bacterial genome
content?